頁籤選單縮合
| 題 名 | Evolution of the Southern Longitudinal Trough in the Incipient Taiwan Arc-Continent Collision Zone and Its Tectonic Implication=南縱海槽的發育及其在弧陸碰撞初發生帶構造演化上的意義 |
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| 作 者 | 傅式齊; 劉家瑄; | 書刊名 | 中國地質學會會刊 |
| 卷 期 | 41:4 1998.11[民87.11] |
| 頁 次 | 頁497-516 |
| 分類號 | 353.1 |
| 關鍵詞 | 地塊轉動; 走向斷層; 拉張盆地; 碰撞初發生帶; Block rotation; Strike-slip fault; Pull-apart basin; Icipient collision zone; |
| 語 文 | 英文(English) |
| 中文摘要 | 南縱海槽位於臺灣南部�甯K半島的東側,是弧陸碰撞初發生帶中的一個 南北狹長形盆地。從詳細的震測層序分析及反射震測剖面構造解釋推知,南 縱海槽的發育可以分為三個階段。在第一個階段中,增積岩體靠弧一側由反 向逆衝斷層抬昇的構造高區上首先產生了一個凹陷區或拉張盆地。在第二個 階段中,受包夾著這個局部凹陷區兩側的走向斷層持續發育的影響,這個拉 張盆地在南--北方向上伸張成為狹長的盆地。第三個階段則為受到呂宋島弧 體塊順時鐘方向旋轉的影響,南縱海槽中的沉積中心軸也產生輕微的順時鐘 方向旋轉。至於南縱海槽最初的形成可能是從(1)兩條走向斷層之間的拉張 盆地,(2)縱谷斷層南端的馬尾狀散開構造,或者(3)反向逆衝斷層抬昇 高區的崩塌這三種可能機制之一所發展出來的。 從南縱海槽發育的過程及臺灣東南海域觀察到的構造形態,再加上前人 古地磁的研究結果,我們提出一個臺灣弧陸碰撞過程中從隱沒到碰撞這個過 渡帶的演化模式。孤前盆地的閉合及臺東海脊的形成是由增積岩體孤側的反 向逆衝斷層作用所引起,但臺灣東南海域受到縱谷斷層與位於呂宋島弧中的 一條左移走向斷層包夾的影響,南縱海槽開始發育。隨後呂宋島孤地塊的旋 轉及孤陸碰撞的持續進行會將南縱海槽閉合,而原為南北走向的隱沒構造岩 體也轉變為北北東--南南西走向的雁行構造形態。現在臺灣東南海域中的海 槽、海脊、島孤等地質單元未來將被擠壓在一起形成海岸山脈向南延伸增積 的部份。 |
| 英文摘要 | The southern Longitudinal Trough (SLT) is a N-S trending elongated trough located just east of the Hengchun in the incipient arc-continent collision zone of offshore southern Taiwan. Detailed seismic sequence analyses and structural interpretation of seismic reflection profiles reveal that the devvelopment of SLT probably involved the following three phases; (1)initial formation of a local depression or pull-apart basin on a structural high of a backthrust wedge; (2)the transformation of the Iocal depression into a N-S trending elongated basin as two parallel marginal faults of the basin drew near; and (3)clockwise rotation of the depocenter axes as the Luzon Arc made the same rotation. Three possibilities are suggested for the initiation of the trough: (1)a pull-apart basin bounded by two juxtaposing strike-slip faults; (2)a horsetail-splay structure developed at the southern end of the Longitudinal Valley Fault; and (3)a basin formed due to collapse of a frontal backthrust wedge. Based on the sequential development of SLT, structural patterns and paleomagnetic data, an evolutionary model is proposed to illustrate how the N-S trending accretionary wedgeforearc basin-volcanic arc system evolves into the NNE trending en echelon structural configuration of the onland Coastal Range. After the initial formation of SLT between the two marginal faults, the Luzon Arc rotated clockwise as they moved into the incipient collision zone. The Longitudinal Valley Fault then extended offshore along the western margin of SLT. In future, if the arc- continent collision proceeds, most of the present SLT would be converted into another Longitudinal Valley bounded by two high- angle thrusts, and the rotated Luzon Arc with the NE segmented blocks and the Taitung Trough would become a new Coastal Range with en echelon structures. |
本系統中英文摘要資訊取自各篇刊載內容。